Investigate an open source alternative to MS Exchange

As part of an investigation for a client who wishes to explore moving away from their current “Cloud” Email provider, I have started investigating open source alternatives to Microsoft Exchange.

MS Exchange Functionality

The open source alternatives to Microsoft Exchange must have the following functionality :

  • Email (kinda obvious)
  • Group Public Folder Access (with assignable email addresses)
  • Calendars (private and shared)
  • Outlook integration
  • Push Email (for Blackberry)

Option 1: Citadel

I was initially drawn to Citadel as a replacement. It’s clearly got a very long history and is mentioned a lot as a replacement for MS Exchange.  Having read about Citadel quite a bit, I decided to download and install it.

Installing Citadel Email

Installation on a fresh install of Ubuntu Server 11.10 was simple enough. I had a working group-ware server up and running within 30 minutes of starting the install process.

Citadel is an odd thing – it’s based on the concept of rooms and floors which allow you to create containers and assign roles to them (e.g. create a room and assign it a role as a public folder).  I’m not saying this is a bad way of doing things, just not quite as intuitive initally. Still I got the hang of it after a few minutes playing.

Public Folders

One of the critical requirements to replace Exchange was to be able to set up Public Folders to accept incoming Emails. I didn’t want these distributing out as email subscribers like a distribution list, I just simply wanted a shared folder with inbound emails that anyone could read and action.  It was not immediately clear on how to create these, but further investigation showed it could be done.


Citadel Shared Calendars

To do this, (remember: think rooms and floors) you need to create a public room on a public floor and give it the type of “Calendar”.


Citadel Outlook Integration

This can be achieved (though you have to buy the connector) through Bynari’s product. This costs $29 per connector with one being required for each installation of Outlook.

I’ll investigate Outlook Alternatives to avoid this cost if possible such as Thunderbird.

Push Email

The Funambol connector for Citadel looks to be now discontinued, so if anyone has any ideas as to some alternatives I’d appreciate any feedback?

Citadel Webmail

The Citadel webmail worked out of the box – the installation was so simple for such a complex product so I’ve got to take my hats off to the team on that.  The “look and feel” is a bit wanting compared to this day and age, but theres no arguing that if you want a Group-ware install that works out of the box then Citadel is certainly a consideration. It may even fit the bill in this case, but I need to do some more playing to check what it does and doesn’t do.

Option 2: Zimbra

I’ve also briefly looked at using Zimbra but was frustrated by the Outlook integration seemingly only being available for “Professional” or paid for versions.  Outlook integration is the absolute show stopper that is preventing the mass adoption of opensource group-ware.

Has anyone else other suggestions of open-source MS Exchange alternatives?


Update: Part 3



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